Harvey Two-Face Dent is a fictional supervillain appearing in American comic books published by DC Comics, commonly as an adversary of the superhero Batman. The character was created by Bob Kane and Bill Finger, and first appeared in Detective Comics #66 (Aug. 1942).
reactivity. 1  the quality or condition of being reactive. 2  Chemistry. the relative capacity of an atom, molecule, or radical to undergo a chemical reaction with another atom, molecule, or compound. 3  Physics. a measure of the deviation from the condition at which a nuclear reactor is critical.
A reactant is one of the inputs in a reaction, that get changed. The word reactant is used in chemistry. A substance that has a reaction and undergoes a change is considered reactant. Reactants (or 'substrates') are two or more elements/ compounds that chemically interact to form a new substance. They are the starting materials for a reaction and are always found at the left side of a chemical equations. A reactant is one of the inputs in a reaction, that get changed.